Hey guys, Johann here. Ever since we announced the Sienci spindle for the Altmill, there has been a tremendous amount of interest from the community in bringing a Sienci-supported spindle option to the LongMill platform. While it has always been our intention to do so, we were busy finishing up the AltMill and other projects, which prevented us from giving this project the due diligence that it deserves.
If you want to read about our previous thoughts, testing, and opinions about spindles for the LongMill, check out this blog post.
The LongMill Spindle and Dust Shoe Kit is now available in our store. First orders are expected to ship August/September 2024
Below is our analysis and additional info about ordering the kit.
TLDR Version
- It’s about half as loud as a router
- Easy to connect
- Offers precise control over your spindle
- New features and functionality when paired with the SuperLongBoard.
- Offers gains in performance over 20,000 rpm
- Orders are open now and will ship August/September 2024
Key benefits
Noise
In a previous survey of the LongMill community, most people placed “lower noise” as their second highest priority feature (only behind auto tool changing).
In our testing, a 1.5kW spindle is consistently 10dBA quieter than the Makita router at every speed, which makes it a drop-in upgrade that is easily half as loud (half the noise every 10dBA). While a water-cooled spindle would be even quieter, we believed that a small amount of extra noise was a reasonable tradeoff to the extra complexity of a water cooling system.
For some context, this air-cooled spindle produces less noise than the quietest of dust collectors/shop vacs in most use cases up to 23,000RPM.
Plug and Play/Easy to Install
The Sienci spindle comes pre-wired, pre-programmed, and connects to your controller with a single RJ11 Cable (a telephone cable). As with all of our other accessories for the LongMill, come with excellent resources and support. We are currently finalizing the installation guide to upload to our resources site soon.
Advanced Spindle Control
Another benefit of a spindle system is that you can control the start/stop and speed of the spindle directly from your g-code sender or gSender. With this digital interface, you:
- Can precisely control the speed of your spindle down to the single RPM
- Know when your spindle is at speed
- Know if your spindle stalls
- Communication between the VFD and gSender to improve the chances for job recovery in the event of a failure
Caveats, Provisos, Warnings, and Disclaimers
Marginal Cutting Performance Gains
This is an area we spent a lot of time and effort digging into since there are varying performance claims floating around the Internet and we’d like to give you our conclusions with some hard numbers. This of course pertains to our product in general, but likely to any spindle kit on the market. We believe we have conducted the most thorough testing and investigation in the hobby space for spindles.
The key takeaway from our testing is that the spindle is not dramatically more powerful than the router. The spindle has more power and torque at higher speeds, while the opposite is true for speeds below 20000 RPM (despite a higher risk of overheating for the Makita).
For 0.25” (¼ inch) tooling, there is little practical difference in cutting performance when upgrading to a spindle since you are limited to 400-500W cutting with the rigidity of the bit. With surfacing, you can use the full power of the spindle, but it also means that you will need to run both the machine and the spindle fast.
SuperLongBoard as a requirement
To take full advantage of the spindle, including the advanced control features detailed above and the all-important partial holding current feature available only with grblHAL, we highly recommend that you upgrade to the SuperLongBoard.
While it is possible to adapt this spindle kit for use on the LongBoard (and we will release more information on how that can be accomplished), here are 6 key disadvantages that you should be aware of:
- We will consider this a DIY configuration and support and resources will be limited
- Start-stop control will be unavailable without a reflash of the firmware and additional components
- The VFD will have to be re-programmed
- Holding current must be applied in full which can overheat the drivers and motors
- No stall detection or any other advanced features that are currently in development
- High-speed machine movements (>4000mm/min) that suit the spindle are unavailable due to legacy driver stability issues.
Dust shoe hose size
The spindle is designed with dust collectors, not shop vacs in mind and as such fits 4” dust hoses by default. To use shop vacs with the dust shoe, you will need to purchase a commonly available 2.5” to 4” adapter (Example found here on Amazon). We are trying to see if we can offer an adapter at some point, but there are no commitments on this item just yet.
Additionally, the original dust shoe used on the LongMill is not compatible with the 80mm spindle. The kit comes with a larger dust shoe included.
Spindle Mount
This spindle is 80mm in diameter and the mount will be included in the LongMill Spindle and Dust Shoe Kit.
The main difference between the AltMill Spindle and Dust Shoe Kit and the LongMill Spindle and Dust Shoe Kit is the addition of the 80mm mount. You can also purchase the mount separately from our store.
Additional Information and Insights
Cutting Volume and Accessories Compatibility
We’ve checked the spindle + dust shoe against every single LongMill configuration ever released (including the MK2 extension kits), and there is no loss to cutting volume to any configuration (the MK2 front feet can technically can collide with the dust shoe, but the overlap is only 2mm (1/16”) and only occurs when you are cutting below the wasteboard).
The story is a bit different with the Vortex which is a lot more height constrained. The additional length of the spindle collet eats into the cutting (and probing) height requirements of the Vortex, and for every machine configuration we recommend raising the feet of the machine up by 1.5” (2 sheets of 0.75” MDF) to restore the original cutting volume.
Weight of Spindle and Mechanical Effects
The new spindle is 2.8kg (6lbs) heavier than the Makita RT0701C router’s 1.8kg (4lbs) which may seem a lot, but according to our calculations and testing, this has a negligible effect on the X and Y axis, requiring only an extra 1-2% of available torque from the steppers motors even accelerating to 5500mm/min. The remaining torque should also be sufficient in making the hypothetical 1.5kW cuts which typically require less than 100N in cutting force.
With regards to the Z-axis, the additional weight can consume up to 27% of total available torque of the motor. Having said that, since boring operations typically involve pushing the bit down into the material, the additional weight is not an issue in such a scenario.
Lastly, it’s also worth mentioning that although the steppers can hold and push the spindle with an adequate amount of force, aggressive cutting can still result in significant deflection of the bit and cause your cuts to come out untrue, so after any aggressive cuts, you should always follow up with a skim/spring or finishing pass to make sure that the surface is accurate and smooth.
Conclusion
While the Makita RT0701 is an excellent option and recommended for most LongMill users, the Spindle Kit offers a high-quality, simple, and well-supported option for the community. To learn more and to order, make sure to check out the store page here.
LongMill Spindle and Dust Shoe Kit
Docs The lead time for this item is 3 days. The LongMill Spindle and Dust Shoe Kit is designed to unleash the capabilities of the LongMill as a plug-and-play replacement for the standard Makita RT0701 router. Each kit comes with: 80mm Dust Shoe 1.5KW 110V Air-Cooled Spindle 110V, 1.5KW, 3-Phase VFD…
11 in stock